An explosion near a sidewalk cafe in an Istanbul suburb injured about 30 people Sunday, and police said they suspected it was caused by a percussion grenade.

The Anatolia news agency reported that the explosion occurred in a trash container in the Bakirkoy district.

Istanbul's chief of police was investigating the blast site and the injured were taken to a nearby hospital, Anatolia said. One victim was in serious condition.

Kurdish militants have left bombs in Istanbul and threatened more attacks after widespread rioting recently in Turkey's Kurdish-populated southeast.